I think there might be an order of magnitude error in your calculations. If each track has a 7 x 2 meter contact patch, that's 14 square meters each, or 112 square meters in total. Which according to the google calculator is equivalent to 1,120,000 square centimeters. Multiplying that by the M1 Abrams ground pressure of 1.09 kgf per square cm, gives 1,220,800 kilograms. Dividing by 1000, we get 1220.8, roughly ten times your figure.
Interestingly, this site: http://www.swcombine.com/rules/?Ground_Vehicles&ID=5
claims a weight of 870 tons, so it makes sense. Additionally, it's supposedly fission powered, and I'm kind of skeptical that a worthwhile fission reactor could fit in 122 tons, as that's about the weight of two Abrams tanks.>>1041748
Actually, most of the "landship" attempts were from around WWI, when transmissions were so inefficient and engines so underpowered that nothing tracked achieved good speed. The Renault FT tank, a light tank from WWI, weighing only 6.5 tons, couldn't manage more than a fast walking pace. Even the Panzer VII Maus, the largest "landship" of WWII was twice as fast, at 12 mph or so. The main drawback to such massive vehicles isn't neccessarily the speed, but it's that they're costly and putting all your eggs in one basket, there really isn't a worthy use case for them. But 12 mph or better would probably be perfectly adequate for a Sandcrawler, there's no particular need for high speed, its main use is as a mobile shelter to protect from the desert conditions, so getting from point a to point b rapidly isn't really a priority, so long as it's faster than you can walk.>>1043100
Star Wars has plenty of stronger materials than we have, so they can probably tolerate much higher core temperatures without meltdown. Sure, the uranium or whatever would still melt at the same point, but they can probably build a containment vessel that can withstand those temperatures and prevent it from leaking out, even if the fuel becomes liquid or even a gas. Non-solid fuel fission reactors have actually been proposed irl for things like rocket engines (because higher temperatures = more power from a given amount of fuel), but none have really become practical yet. But with Star Wars technology it seems plenty plausible.>"walking" vehicles
Probably would have too high ground pressure. Would only make sense where you have solid, but uneven ground. Whereas Tatooine has sand everywhere, but for the most part it's reasonably smooth.>>1044987
According to Wookieeepedia, they were brought to Tatooine by mining companies long ago, and were left behind when the mines closed.